San Francisco Subway Tests Wi-Fi

A startup says it can give subway riders wireless Internet access that's faster than most home broadband in the U.S.

Tests at stations and on a special stretch of track in the Bay Area Rapid Transit (BART) system around San Francisco showed that Wi-Fi Rail's patent-pending technology delivered more than 15M bps (bits per second) of wireless throughput to riders and people waiting for trains, the company said. Wi-Fi Rail hopes to roll out such networks on rail systems around the world and charge commuters for access.

Commuter rail, with thousands of daily riders, could represent a rich opportunity for public wireless Internet access. Wi-Fi hotspots in airports and coffee shops have drawn some paying users, but the hotspots are useful more for occasional than for regular use. And citywide public Wi-Fi networks, often planned out with local governments, have run into political and business problems.

Wi-Fi Rail, founded in 2006 and based near Sacramento, would build two kinds of Wi-Fi networks: one in the cars and one around the tracks, said Michael Cromar, Wi-Fi Rail's chief financial officer. Passengers would log in to access points on each car, and each car's network would lock on to one access point after another along the rail system. The trackside access points, in turn, would feed traffic onto fiber-optic lines. Roaming would be handled by the in-car network and be transparent to users, Cromar said.

Even better than typical home broadband, the network can deliver its average 15M bps speed both upstream and downstream, according to Wi-Fi Rail. Passengers would share that link, but in tests, there was no noticeable slowdown between one passenger and eight passengers using the network, Cromar said. The system worked with the trains moving at speeds as high as 65 miles per hour.

The company tested its technology in both underground and above-ground parts of the BART system. Above ground, Wi-Fi Rail used standard outdoor access points with line-of-sight antennas to form a link from trains as they went by. In an underground test, the company used "leaky" coaxial cable, a technology some rail systems already use for exchanging operational data with cars, according to Cromar. The leaky cable is deliberately unshielded so signals traveling along it can be picked up all through a tunnel.

In-car tests took place on a 2.6-mile BART test track last month, as well as on a stretch of tunnel in San Francisco. Another part of the test proved such a service can draw customers, Cromar said. Wi-Fi Rail set up regular access points in four underground stations in downtown San Francisco and let people waiting for trains register and use the network for free. Without any publicity, more than 6,400 people signed up in less than six months, he said.

Although BART hosted the tests, it hasn't made a deal to have such a network deployed, Cromar said. But Wi-Fi Rail has talked with one interested transit system in the U.S. and is working with a partner to approach a rail system in another country, he said. The company said its technology is ready to go and could be used for anything that follows a predetermined path, including highways.